Waste lubricating oil regeneration method

Abstract

The invention relates to a waste lubricating oil regeneration method, which adopts the following specific production processes: demetallization, dehydration, light hydrocarbon removal, residual oil removal, polar component removal, dechlorination and hydrofining, the waste lubricating oil is used as a raw material for processing to produce high-quality base oil, and the obtained base oil has the chroma (Sibaud) of more than or equal to + 28, the kinematic viscosity (40 DEG C) of 25-35 mm < 2 > / s, the open flash point of more than 200 DEG C and the viscosity index of more than or equal to 110. The sulfur content is less than or equal to 1mg / kg; the method is safe, environmentally friendly, mild in operation condition, low in equipment requirement, high in operation flexibility, low in production and processing cost and remarkable in economic benefit.

Description

Technical Field

[0001] The present invention relates to the field of petrochemical technology, and in particular to a waste lubricating oil regeneration method. Background Art

[0002] At present, lubricants are widely used in chemical, textile, machinery and other industries. With the further promotion of economic globalization, especially the rapid development of the automobile industry, and the strengthening of environmental protection and energy-saving requirements, although the total supply of lubricants has not increased significantly, the demand for high-end lubricants is growing. Lubricants are mainly composed of base oil and additives. Base oil is the main component of lubricants and plays an important role in the basic properties of lubricants.

[0003] Lubricating oil has the functions of reducing friction, cleaning and sealing machinery, protecting machinery, lubricating and cooling machinery, and preventing rust. After long-term use of lubricating oil in equipment, part of the base oil is oxidized, degraded, and deteriorated, and the additives are also consumed and deteriorated, forming acidic oxides, colloid asphalt, etc. The deterioration process of lubricating oil is a very complicated process. In this process, on the one hand, the physical impurities mixed from the outside world pollute the lubricating oil, and on the other hand, the chemical impurities produced by the oxidation and deterioration of the lubricating oil pollute the lubricating oil. For seriously deteriorated lubricating oil, not only the lubrication effect deteriorates, but also the acidic oxides in it will accelerate the corrosion of metal equipment. If the lubricating oil that has deteriorated to a certain extent is not replaced in time, it will have an adverse effect on the machinery. Therefore, in order to enable the use of machinery and equipment for a longer time, the lubricating oil must be replaced with a new lubricating oil after a certain period of use and reaches the oil change standard. The replaced lubricating oil becomes waste lubricating oil.

[0004] There are four main methods for treating waste lubricating oil in my country: discarding, road oiling, incineration and using as fuel after removing heavy metals, and regenerated base oil after treatment through waste lubricating oil regeneration process. The first three methods of treating waste lubricating oil pollute the environment to a greater or lesser extent, and cannot better develop the potential value of waste lubricating oil. The regeneration of waste lubricating oil not only saves resources, but also alleviates the shortage of oil resources, increases the value of waste lubricating oil, and has less pollution to the environment. Regeneration of waste lubricating oil into lubricating oil is the best choice for treating waste lubricating oil.

[0005] At present, waste lubricating oil regeneration mainly includes solvent extraction and hydrogenation. Solvent extraction mostly uses mixed solvents for extraction, the extraction ratio is not high, the base oil yield is low, and the commonly used extractants are toxic and environmentally unfriendly. Hydrogenation mostly uses hydrorefining-hydroisomerization reaction process, and the catalyst is mostly selected as precious metal catalyst, which has a high production cost. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, the present invention provides a waste lubricating oil regeneration method which has the advantages of simple operation, high recovery rate and stable product quality.

[0007] In order to solve the above technical problems, the technical solution adopted in this application is as follows: a waste lubricating oil regeneration method, comprising the following steps:

[0008] S1: Raw material pretreatment

[0009] 1.1. The waste lubricating oil is allowed to settle in the raw material tank to remove metal impurities;

[0010] 1.2. The raw materials obtained after static sedimentation enter the flash tower through heat exchange, and the water is removed in the flash tower;

[0011] 1.3. After flash evaporation, the material enters the lightness removal tower to remove light hydrocarbon components;

[0012] 1.4. After heat exchange, the material from the light-removal tower enters the vacuum distillation tower to remove the residual oil components, and obtains the distillate oil after rectification;

[0013] 1.5. The distillate oil enters the extraction tower, where the colloid, asphaltene and other highly polar components in the distillate oil are removed by solvent extraction;

[0014] 1.6. The extracted solution enters the dechlorination reactor after heat exchange, and is washed with water and flashed to obtain the hydrogenation refining raw material;

[0015] S2: Hydrofining reaction

[0016] 2.1. Hydrorefining raw materials undergo hydrorefining reaction to remove impurities such as sulfur, nitrogen and aromatics in the hydrorefining raw materials;

[0017] 2.2. The hydrogenation reaction products are cut by the fractionation system to obtain high-quality base oil products.

[0018] Preferably, the water content of the raw waste lubricating oil in step (1.1) is ≤3%, the distillate oil content is ≥75%, the distillation tail oil content is ≤10%, and the open flash point is ≥160°C.

[0019] Preferably, in step (1.1), the sedimentation temperature of the raw material tank is 40-50°C.

[0020] Preferably, in step (1.1), the distance between the outlet of the raw material tank and the bottom is greater than or equal to 40 cm (this distance prevents the settled metal impurities from coming back up, ensuring that the subsequent raw materials do not contain metal impurities).

[0021] Preferably, the operating conditions of the flash tower in step (1.2) are: temperature 100 to 250° C., pressure -0.1 to -0.02 KPa.

[0022] Preferably, the operating conditions of the lightness removal tower in step (1.3) are: temperature 200 to 300° C., pressure -0.2 to -0.05 MPa.

[0023] Preferably, the operating conditions of the vacuum distillation tower in step (1.4) are: temperature 300 to 400° C., pressure -0.2 to -0.05 MPa.

[0024] Preferably, in step (1.5), the extraction solvent is a methyl pyrrolidone mixture, the mixture is nitrogen methyl pyrrolidone and ethanolamine, the mass percentage of ethanolamine in the methyl pyrrolidone mixture is 0.005-0.02%; the ratio of the extractant to the distillate oil is 0.6:1-1.2:1, and the extraction temperature is 40-70°C; the above-selected extraction reagent has the advantages of low toxicity, mild extraction conditions and high extraction rate, and the content of heavy aromatics in the distillate oil after solvent extraction is 0.3-3.2%.

[0025] Preferably, the dechlorination temperature in step (1.6) is 250-350° C., and the dechlorination agent used for dechlorination is an alkaline mixture: potassium alkali (such as potassium hydroxide) and sodium alkali (such as sodium hydroxide) are mixed in a weight ratio of 3:7 to 5:5.

[0026] Preferably, the chlorine content in the hydrotreating reaction raw material obtained after raw material pretreatment is less than 2 mg / kg.

[0027] Preferably, the hydrogenation catalysts selected for the hydrorefining reaction part are deep hydrodesulfurization catalyst A and hydrodearomatization catalyst B (the hydrodesulfurization catalyst A and hydrodearomatization catalyst B here are catalysts developed by Jinda Company, the main metal components are W, Mo, Ni, Co, and the commonly used isomerization catalyst is a precious metal catalyst. The production cost of the precious metal isomerization catalyst is much higher than that of the hydrorefining agent selected in the present invention). The hydrorefining part comprises three reactors, the first reactor is filled with catalyst A, and the second and third reactors are filled with catalyst B; the deep hydrodesulfurization catalyst A can adopt the deep hydrodesulfurization catalyst prepared in application number 201711400168.1; the hydrodearomatization catalyst B can adopt the hydrodearomatization catalyst prepared in application number 202010331191.5.

[0028] Preferably, the hydrofining reaction conditions are: reaction pressure 8-15 MPa, reaction temperature 280-380°C / 260-380°C / 230-320°C, hydrogen-oil ratio 800-1800:1, reaction space velocity 0.3-1.2h -1 .

[0029] Advantages and beneficial effects of this application:

[0030] 1. The content of distillate oil in the waste lubricating oil selected in the present application is ≥75%. After raw material pretreatment and hydrofining treatment, the base oil yield obtained is ≥64%. Therefore, the treatment process of the present application has a high yield of base oil obtained by processing waste lubricating oil; the hydrofining reaction raw material obtained after raw material pretreatment can meet the Class I base oil standard, and Class II base oil can be obtained after hydrofining, that is, Class I base oil is obtained by hydrofining to obtain Class II base oil.

[0031] 2. In the raw material pretreatment part of this application, the raw materials are extracted and then subjected to dechlorination reaction, and the chlorine content in the raw materials of the hydrofining part is controlled within 2 mg / kg. When the chlorine content is high, the salts and acidic substances generated during the reaction will cause blockage and corrosion to the reactor and equipment. In order to avoid corrosion of the equipment, reduce the impact of hydrofining by-products on the hydrogenation reaction, and protect the catalyst, the chlorine content is controlled within 2 mg / kg. The above control can ensure product quality.

[0032] 3. The present application adopts the following main specific production processes: demetallization - dehydration - removal of light hydrocarbons - removal of residue oil - removal of polar components - dechlorination - hydrofining, and processes waste lubricating oil as raw material to produce high-quality base oil. The method is safe and environmentally friendly, has mild operating conditions, low equipment requirements, great operational flexibility, low production and processing costs, and significant economic benefits.

[0033] 4. The process of this application produces 150SN base oil, and the base oil obtained has a color (Saybolt) ≥ +28 and a kinematic viscosity (40°C) of 25-35 mm 2 / s, open flash point>200℃, viscosity index≥110, aromatics≤1%, sulfur content≤1mg / kg. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a flow chart of the device for the regeneration method of this application.

[0035] As attached Figure 1 Shown: 1. Raw material tank, 2. Intermediate tank, 3. Flash tower, 4. Dehydrogenation tower, 5. Vacuum tower, 6. Extraction tower, 7. Distillation tower, 8. Dechlorination reactor, 9. Water washing tower, 10. Flash tower, 11. First reactor, 12. Second reactor, 13. Third reactor, 14. Fractionation tower, 15. Fractionation tower. DETAILED DESCRIPTION

[0036] The present invention can be further described in detail with reference to the following examples; however, the following examples are merely illustrative, and the present invention is not limited to these examples.

[0037] The specific embodiment of the present application adopts the device flow chart of the regeneration method shown in Figure 1, in which: first, the raw material is stored in the raw material tank 1, then enters the intermediate tank 2, and then enters the flash tower 3, and enters the light removal tower 4 from the flash tower 3 for light removal treatment. After the light removal is completed, it enters the vacuum tower 5, and then enters the extraction tower 6 for extraction. After the extraction is completed, it enters the distillation tower 7 for distillation, and then enters the dechlorination reactor 8, the washing tower 9 and the flash tower 10 in sequence. After the treatment is completed, it enters the first reactor 11, the second reactor 12 and the third reactor 13 for hydrofining reaction. After the hydrofining reaction is completed, it is distilled through the fractionation tower 14 and the fractionation tower 15 to obtain Class II base oil; each device in the flow chart of the present application can adopt the conventional device structure in the industry, and the most important invention point of the present application lies in the design of the process of the present application, the setting of corresponding parameters and the use of various materials.

[0038] Example 1

[0039] A method for regenerating waste lubricating oil comprises the following steps:

[0040] Step 1: First, waste lubricating oil (specific waste lubricating oil meets the above specifications: moisture content ≤ 3%, distillate oil content ≥ 75%, distillate tail oil content ≤ 10%, open flash point ≥ 160°C) (the above are the basic properties of the main raw materials in the waste lubricating oil. Considering the recovery rate of the lubricating oil mentioned later, if the distillate oil content in the raw material is too low, the economic significance of the recovery is not great, and the 150SN base oil of the present application cannot be obtained) is removed from the raw material tank 1 after standing and settling at 45°C to remove metal impurities. After settling, the raw material is discharged from about 40 cm from the bottom and enters the intermediate tank 2. The raw material in the intermediate tank 2 enters the flash tower 3 after heat exchange. The flash tower 3 (-0.02MPa, 125°C) is used to remove water, and the material after flashing enters the lightness removal tower 4 (-0.1MPa, 220°C) to remove light hydrocarbon components. The material after the lightness removal tower 4 enters the vacuum tower 5 (-0.1MPa, 340°C) after heat exchange to remove the residual oil component, and obtains the distillate oil after rectification. The distillate oil enters the extraction tower 6, and the solvent (the mass percentage of ethanolamine in the methyl pyrrolidone mixture is 0.012%) at 55°C is used to extract and remove the colloid, asphaltene and other strong polar components in the distillate oil. The ratio of the extractant to the distillate oil is 0.8:1, and the heavy aromatic hydrocarbon content in the distillate oil after extraction is 1.8%. After extraction, the solvent oil passes through the distillation tower 7 (-0.05MPa, 220°C) to remove the extractant and impurities to obtain the regenerated base oil;

[0041] Step 2, the base oil regenerated from the waste oil treated in step 1 enters the dechlorination reactor 8 (285°C, the dechlorinating agent is an alkaline mixture of potassium hydroxide and sodium hydroxide in a weight ratio of 3:7) after heat exchange, the material coming out of the dechlorination reactor 8 enters the water washing tower 9 (65°C) after heat exchange, the material coming out of the water washing tower 9 is separated by sedimentation and then passes through a filter into a flash tower 10 (-0.02MPa, 125°C) to remove moisture, and the obtained dechlorinated base oil is used as a hydrogenation raw material;

[0042] Step 3, using the dechlorinated base oil obtained after pretreatment in step 2 as a raw material, pressurized by a raw material pump and mixed with hydrogen, entering the first reactor 11 loaded with catalyst A (deep hydrodesulfurization catalyst prepared in Example 1 in Application No. 201711400168.1) and the second reactor 12 and the third reactor 13 loaded with catalyst B (hydrodearomatization catalyst prepared in Example 1 in Application No. 202010331191.5), and carrying out a hydrofining reaction at 12MPa, 350°C / 350°C / 240°C (the corresponding temperatures in the first reactor, the second reactor and the third reactor, respectively), and the hydrofining reaction conditions are: hydrogen-oil ratio 1000:1, reaction space velocity 0.8h -1 Thus, the impurities such as sulfur, nitrogen and aromatic hydrocarbons in the dechlorinated base oil are removed, and then distilled through the distillation tower 14 and the distillation tower 15, and finally the Class II base oil is obtained. The properties of the obtained base oil are shown in Table 1. After the distillate oil in the waste lubricating oil is treated by raw material pretreatment and hydrofining, the base oil yield is 73.6%.

[0043] Table 1 Base oil product analysis

[0044]

[0045] Example 2

[0046] A method for regenerating waste lubricating oil comprises the following steps:

[0047] Step 1, waste lubricating oil (water content 2.1%, distillate oil content 85%, distillation tail oil content 3.1%, open flash point 186 ° C), after sedimentation in raw material tank 1, remove metal impurities, after sedimentation, the raw material is discharged from about 40 cm from the bottom and enters the intermediate tank 2, the raw material in the intermediate tank 2 enters the flash tower 3 after heat exchange, and the water is removed in the flash tower 3 (-0.02MPa, 120 ° C), the material after flash evaporation enters the light removal tower 4 (-0.1MPa, 230 ° C) to remove the light hydrocarbon components, the material after the light removal tower enters the heat exchange The residual oil component is removed by vacuum tower 5 (-0.1MPa, 350°C), and distillate oil is obtained after rectification. The distillate oil enters extraction tower 6, and the solvent (the mass percentage of ethanolamine in the methyl pyrrolidone mixture is 0.01%) is used to extract and remove the colloid, asphaltene and other strong polar components in the distillate oil at 58°C. The ratio of the extractant to the distillate oil is 0.7:1. The content of heavy aromatics in the distillate oil after extraction is 2.3%. The solution after extraction passes through distillation tower 7 (-0.1MPa, 220°C) to remove the extractant and impurities to obtain regenerated base oil.

[0048] Step 2, the base oil from waste oil regeneration enters the dechlorination reactor 8 (290° C., the dechlorinating agent is an alkaline mixture of potassium hydroxide and sodium hydroxide in a weight ratio of 5:5) after heat exchange, the material coming out of the dechlorination reactor 8 enters the water washing tower 9 (70° C.) after heat exchange, the material coming out of the water washing tower 9 is separated by sedimentation and then passes through a filter into a flash tower 10 (-0.02MPa, 120° C.) to remove moisture, and the obtained dechlorinated base oil is used as a hydrogenation raw material;

[0049] Step 3: The dechlorinated base oil obtained by pretreatment is used as a raw material, which is pressurized by a raw material pump and mixed with hydrogen, and then enters the first reactor 11 loaded with catalyst A (deep hydrodesulfurization catalyst prepared in Example 1 of Application No. 201711400168.1) and the second reactor 12 and the third reactor 13 loaded with catalyst B (hydrodearomatization catalyst prepared in Example 1 of Application No. 202010331191.5). Hydrofining reaction is carried out at 10MPa, 330 / 330 / 240°C, and the hydrofining reaction conditions are: hydrogen-oil ratio 1200:1, reaction space velocity 1.0h -1 The impurities such as sulfur, nitrogen and aromatic hydrocarbons in the dechlorinated base oil are removed, and then distilled in the distillation tower 14 and the distillation tower 15 to obtain the Class II base oil. The properties of the obtained base oil are shown in Table 2. After the distillate oil in the waste lubricating oil is subjected to raw material pretreatment and hydrofining treatment, the base oil yield is 75.2%.

[0050] Table 2 Base oil product analysis

[0051]

[0052]

[0053] The above examples and test results show that the 150SN base oil produced by the present application has a chromaticity (Saybolt) of ≥ +28 and a kinematic viscosity (40°C) of 25 to 35 mm 2 / s, open flash point>200℃, viscosity index≥110, aromatics≤1%, sulfur content≤1mg / kg; when the content of distillate oil in waste lubricating oil is ≥75%, the base oil yield obtained is ≥64%. Therefore, the base oil obtained by the regeneration method of the present application has the advantages of simple operation, high recovery rate and stable product quality.

Claims

1. A method for regenerating waste lubricating oil, characterized in that it comprises the following steps: S1: Raw material pretreatment 1.

1. The waste lubricating oil is allowed to settle in the raw material tank to remove metal impurities; 1.

2. The raw materials enter the flash tower after heat exchange, and the water is removed in the flash tower; 1.

3. After flash evaporation, the material enters the lightness removal tower to remove light hydrocarbon components; 1.

4. After heat exchange, the material from the light-removal tower enters the vacuum distillation tower to remove the residual oil components, and obtains the distillate oil after rectification; 1.

5. The distillate oil enters the extraction tower, where the colloid and asphaltene strong polar components in the distillate oil are removed by solvent extraction; 1.

6. The extracted solution enters the dechlorination reactor after heat exchange, and is washed with water and flashed to obtain the hydrogenation refining raw material; S2: Hydrofining reaction 2.

1. Hydrofining feedstock After the hydrofining reaction, sulfur, nitrogen and aromatic impurities in the hydrofining feedstock obtained by pretreatment are removed; 2.

2. The hydrogenation reaction products are cut by the fractionation system to obtain high-quality base oil products.

2. The waste lubricating oil regeneration method according to claim 1, characterized in that: The moisture content of the raw waste lubricating oil described in step (1.1) is ≤3%, the distillate oil content is ≥75%, the distillation tail oil content is ≤10%, and the open flash point is ≥160°C; the sedimentation temperature in step (1.1) is 40-50°C, and the distance from the outlet of the raw material tank to the bottom is greater than or equal to 40cm.

3. The waste lubricating oil regeneration method according to claim 1, characterized in that: The operating conditions of the flash tower in step (1.2) are: temperature 100 to 250° C., pressure -0.1 to -0.02 KPa.

4. The waste lubricating oil regeneration method according to claim 1, characterized in that: The operating conditions of the lightness removal tower in step (1.3) are: temperature 200 to 300° C., pressure -0.2 to -0.05 MPa.

5. The waste lubricating oil regeneration method according to claim 1, characterized in that: The operating conditions of the vacuum distillation tower in step (1.4) are: temperature 300 to 400° C., pressure -0.2 to -0.05 MPa.

6. The waste lubricating oil regeneration method according to claim 1, characterized in that: In step (1.5), the extraction solvent is a methyl pyrrolidone mixture, the ratio of the extractant to the distillate oil is 0.6:1 to 1.2:1, and the extraction temperature is 40 to 70° C.; the content of heavy aromatics in the distillate oil after solvent extraction is 0.3 to 3.2%.

7. The waste lubricating oil regeneration method according to claim 1, characterized in that: In step (1.6), the dechlorination temperature is 250-350° C., and the dechlorinating agent is an alkaline mixture of potassium alkali and sodium alkali in a weight ratio of 3:7-5:

5.

8. The waste lubricating oil regeneration method according to claim 1, characterized in that: The chlorine content in the raw material for hydrogenation refining reaction obtained after raw material pretreatment is less than 2 mg / kg.

9. The waste lubricating oil regeneration method according to claim 1, characterized in that: The hydrogenation catalysts selected for the hydrorefining reaction part in the step S2 are deep hydrodesulfurization catalyst A and hydrodearomatization catalyst B, the deep hydrodesulfurization catalyst A adopts the deep hydrodesulfurization catalyst prepared in application number 201711400168.1; the hydrodearomatization catalyst B adopts the hydrodearomatization catalyst prepared in application number 202010331191.5; the hydrorefining part comprises three reactors, the first reactor is filled with catalyst A, and the second reactor and the third reactor are filled with catalyst B.

10. The waste lubricating oil regeneration method according to claim 1, characterized in that: Hydrogenation refining reaction conditions: reaction pressure 8-15MPa, reaction temperature 280-380℃ / 260-380℃ / 230-320℃, hydrogen-oil ratio 800-1800:1, reaction space velocity 0.3-1.2h -1 The content of distillate oil in the selected waste lubricating oil is ≥75%. After raw material pretreatment and hydrofining treatment, the base oil yield is ≥64%.

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